Alkyltetramethyldisiloxane

ABSTRACT

ALKYLETRAMETHYLDISLOXANES IN WHICH THE ALKYL GROUP HAS FROM 12 TO 45 CARBON ATOMS ARE DISCLOSED. THE ALKYLTERTRAMETHYLDISILOXANES ARE USEFUL AS EVAPORATION ACCELERATORS.

United States Patent 3,576,029 ALKYLTETRAMETHYLDISILOXANE Loren A. Haluska, Midland, Mich., assignor to Dow Corning Corporation, Midland, Mich. No Drawing. Filed Aug. 15, 1968, Ser. No. 752,749 Int. Cl. C07f 7/08 US. Cl. 260448.2 2 Claims ABSTRACT OF THE DISCLOSURE Alkyltetramethyldisiloxanes in which the alkyl group has from 12 to 45 carbon atoms are disclosed. The alkyltetramethyldisiloxanes are useful as evaporation accelerators.

This invention relates to alkyltetramethyldisiloxanes.

An object of the present invention is to provide a new class of alkyltetramethyldisiloxanes which are useful as evaporation accelerators.

The present invention relates to an alkyltetramethyldisiloxane of the formula (CH3): (CH3):

(OuH2n-l-1)S1oSiH wherein n is an integer of from 12 to 45 inclusive.

The alkyltetramethyldisiloxanes of the present invention can best be prepared by reacting an a-olefin with H(CH SiCl in the presence of a platinum catalyst, such as chloroplatinic acid. The resulting product has a formula (CnH2u+l) $101 This alkyldimethylchlorosilane and H(CH SiCl are mixed and hydrolyzed. To insure the desired end-product, the H(CH SiCl is used in excess such as two moles of H(CH SiCl to one mole of the alkyldimeth ylchlorosilane. The reaction mixture is distilled after hydrolysis to recover the product having a formula (CH3)2 (CHah (CnH2n-H) SlOSiH The a-olefin can be any alkene which has a carboncarbon double 'bond at a terminal carbon atom and has 12 to 45 carbon atoms per molecule. The a-olefin can be either straight chained or branched and include, for

example, a-dodecene, a-pentadecene, a-octadecene, w nonadecene,

CH CH (CH CH CH =CH (CH CH(CH CH (CH CH 2= 2) z'z s, 2= 2)10 3]2 2= 2 3 2) s al 2 CH CH (CH CH CH CH (CH CH CH =CH(CH CI-I z= 2)12 a) 2)4 3)2( 2)7 3 and The alkyltetramethyldisiloxaues of the present invention can include, for example CHaCHa HM a)2 CH3(CH2)3CH(CH2)9Si-O-SiH (CH3)2 (CH3)?! Q)? (CHM I aM M The alkyltetramethyldisiloxanes of the present invention are particularly useful as evaporation accelerators. The alkyltetramethyldisiloxanes are applied to the surface of an aqueous body which is exposed to a gaseous atmosphere. The amount of alkyltetramethyldisiloxane applied is determined by the desired results and the temperature and movement of the gaseous atmosphere or aqueous body as well as the particular nature of both the gaseous atmosphere and the aqueous body. The alkyltetramethyldisiloxane can be used to increase the evaporation rate to cause increased cooling or it can be used to dry an aqueous body quicker.

Unwanted stagnant aqueous bodies, such as ponds or swamps, can be dried quicker and therefore the land can be put to work sooner.

The alkyltetramethyldisiloxanes can be applied to the aqueous body as is or in the form of an organic solution or by any other means suitable to disperse the compound over the aqueous surface.

The following examples are illustrative only and should not be construed as limiting the invention which is properly delineated in the appended claims.

EXAMPLE 1 (A) A mixture of octadecene-l, H(CH SiCl and chloroplatinic acid was heated in a high pressure bomb. The resulting mixture was distilled and a product collected which was octadecyldimethylchlorosilane.

A mixture of 1136 g. of H(CH SiCl and 2070 g. of the octadecyldimethylchlorosilane was hydrolyzed. The hydrolyzed product was washed until neutral with a mixture of water and sodium bicarbonate. The resulting mixture was distilled and 1457.2 g. of

was recovered.

(B) A ten weight percent solution of (CH3): (CHM CH (CHz)17SiO-SiH in diethyl ether was prepared. Ten drops of the ether solu tion were placed on the surface of 100 g. of tap water in a 250 ml. stainless steel cup. The resulting assembly was placed in a controlled atmosphere of relative humidity and 68 F. The weight of the cup, water and This particular solution was used as a comparison to show the unique properties of the alkyltetramethyldisiloxanes of the present invention.

The results below are the weight percentages of Water lost in a given period of time under the test conditions.

C HZ O H (G H2) 3CH(CH H9 H3 That which is claimed is:

e ce t 1. An alkyltetramethyldisiloxane of the formula Percent water loss atter increase over (CH3): (CH3): Compound 1 day 2days 5 days 7 days control 1 Control 7 3 14 7 u 47 2 (ODHM) skowsm (Elia 6113 h wherein n is an integer of from 12 to 45 inclusive. ClSH37si O siH 113 44.9 651 319 The allq ltetramethyldisiloxane in accordance with claim 1, m which 11 1s 18. CH3 CH: 30 f E Re erences Cited 3. CnH31S1-0sloH 4.5 10.4 31.7 44.1 -6.6 UNITED STATES PATENTS CH CH 2,491,843 12/1949 W1lcock 260448.2(H) 3 3 2,519,881 8/1950 Brewer 260448.2(H)

EXAMPLE 2 JAMES E. POER, Primary Examiner When the following olefins are reacted with P. F. SHAVER, Assistant Examiner H(CH3)2SiC1 US. Cl. X.R.

and the product is hydrolyzed with H(CH SiCl in a 260448.2R 

